1. Field of the Invention
The present invention relates to the field of liquid crystal display, and more particularly to a method for laminating a polarization film.
2. The Related Arts
Liquid crystal displays (LCDs) have a variety of advantages, such as thin device body, low power consumption, and being free of radiation, and are thus widely used. Most of the LCDs that are currently available in the market are backlighting LCDs, which comprise an enclosure, a liquid crystal panel mounted in the enclosure, and a backlight module fixed in the enclosure. The operation principle of the liquid crystal panel is that, with liquid crystal molecules interposed between two parallel glass substrates, application of electricity is selectively carried out to control the liquid crystal molecules to change direction in order to refract out light emitting from the backlight module for generating images. Since the liquid crystal panel itself does not emit light, light must be provided by the backlight module in order to normally display images. Thus, the backlight module is one of the key components of an LCD. The backlight modules can be classified in two types, namely a side-edge backlight module and a direct backlight module, according to the position where light gets incident. The direct backlight module comprises a light source, such as a cold cathode fluorescent lamp (CCFL) or a light-emitting diode (LED), which is arranged at the backside of the liquid crystal panel to form a planar light source directly supplied to the liquid crystal panel. The side-edge backlight module comprises an LED light bar, serving as a backlight source, which is arranged at an edge of a backplane to be located rearward of one side of the liquid crystal panel. The LED light bar emits light that enters a light guide plate (LGP) through a light incident face at one side of the light guide plate and is projected out of a light emergence face of the light guide plate, after being reflected and diffused, to pass through an optic film assembly to form a planar light source for the liquid crystal panel.
Referring to FIG. 1, a liquid crystal display generally comprises: a backlight module 100, a mold frame 300 mounted on the backlight module 100, a liquid crystal display panel 500 positioned on the mold frame 300, and a bezel 700 mounted on the liquid crystal display panel 500. The backlight module 100 comprises: a backplane 110, a backlight source 130 mounted in the backplane 110, a reflection sheet 150 arranged in the backplane 110, a light guide plate 170 arranged above the reflection sheet 150, and an optic film assembly 190 arranged above the light guide plate 170. The mold frame 300 carries and supports the liquid crystal display panel 500 and the bezel 700 and the backplane 110 of the backlight module 100 are fixed together to form the liquid crystal display. A conventional liquid crystal display panel 500 (as shown in FIG. 2) comprises a color filter (CF) substrate 520, a thin-film transistor (TFT) substrate 540 that is opposite to and bonded to the CF substrate 520, liquid crystal 560 interposed between the CF substrate 520 and the TFT substrate 540, and a sealing frame 580 that is arranged between the CF substrate 520 and the TFT substrate 540 and is located along a circumferential margin of the CF substrate 520. The CF substrate 520 comprises a first glass substrate 522, a color filter 524 formed on a surface of the first glass substrate 522 that faces the TFT substrate 540 and a first polarization film 526 formed on a surface of the first glass substrate 522 that is away from the TFT substrate 540. The TFT substrate 540 comprises a second glass substrate 542, a thin-film transistor 544 formed a surface of the second glass substrate 542 that faces the CF substrate 520, and a second polarization film 546 formed on a surface of the second glass substrate 542 that is away from the CF substrate 520. Light emitting from the backlight module 100 passes through and is polarized by the second polarization film 546 and then enters the liquid crystal 560, whereby the molecules of the liquid crystal 560 are driven by the TFT transistor 544 to rotate, so as to have the light incident onto the CF substrate 520 to be then polarized by the first polarization film 526 and projected out, allowing human eyes to see images displayed on the liquid crystal display panel 500.
Conventionally, a polarization film is laminated on a glass substrate by being pressed by a roller of a polarization film lamination machine and is then subjected to a de-bubbling process to remove air bubbles present between the polarization film and the glass substrate in order to have the polarization film tightly and flat laminated on the glass substrate and to eliminate the influence of displaying performance by the air bubbles. However, the conventionally used process that uses the roller of the polarization film lamination machine to press and laminate and thus attach the polarization film to the glass substrate generally causes more air bubbles between the polarization film and the glass substrate, making the de-bubbling process complicated in operation, consuming extended time, thereby leading to low manufacture efficiency and high manufacture cost of the liquid crystal display panel.